The S slip has been in use to make connection on a duct system for many years. Because of the shape of an S slip when the pressure is high the section of the S slip that is in the air stream acts as a scoop and allows the air to escape out of the duct. This new S slip with openings along one edge allows the air to pass through the S slip and back into the duct. The sides of the duct are connected with a drive slip. Because of the way the S slip and drive come together at the corners it leaves an opening. In order to make a tight connection, we insert the U shape metal holder with a sealant into the end of the S slip. When the drive slip is knocked over the S slip the sealant, which can be made of fiberglass, makes a tight connection.